Multiphysics problems are encountered when the response of a system is affected by the interaction between several distinct physical fields (e.g., structural deformation, fluid flow, electric field, temperature, pore-pressure, …).

Many problems in engineering and science involve some level of coupling between different physical fields. In the past, due to the lack of computational capabilities, these coupling effects were either ignored or taken into account very approximately. However, with the current analysis capabilities available in ADINA, many
important multiphysics coupling effects can now be included accurately.
By including these coupling effects, the analyses provide deeper
insight into the performance of designs, leading to more economical and safer products, and also to a better understanding of the causes and consequences of natural phenomena [1].

Schematic of Multiphysics Capabilities of ADINA

Mathematically, multiphysics problems are described by a set of coupled partial differential equations (PDEs). The solution of these equations poses a challenge regarding the robustness of the algorithms to handle such interactions in a general and efficient manner.

The ADINA Multiphysics package includes all ADINA solvers for solids and
structures, heat transfer, CFD, and also a comprehensive array of
multiphysics capabilities tightly integrated in one program:

Fluid-structure interaction (FSI)

Thermo-mechanical coupling (TMC)

Structural-pore pressure coupling (porous media)

Thermal-fluid-structural coupling

Electric field-structural coupling (piezoelectric)

Thermal-electrical coupling (Joule heating)

Acoustic fluid-structural coupling

Fluid flow-mass transfer coupling

Fluid flow-electromagnetic coupling

The multiphysics capabilities of ADINA are unique both in their breadth and depth. Using these capabilities, not only a wide range of interactions between different physical fields can be considered, but each of these fields is treated in a general form without compromise on accuracy.

Fluid-Structure Interaction (FSI)

ADINA FSI offers comprehensive capabilities for solving problems involving the interaction between general nonlinear structures and general Navier-Stokes fluid flow all tightly integrated in a single program.

The solution of fully coupled thermo-mechanical problems can be performed with ADINA TMC. In this class of problems, the temperature distribution affects the structural deformation and the structural deformation may affect the temperature distribution.

This multiphysics problem is characterized by the coupling between the pore pressure and the deformation of a porous material (e.g., soil, biological tissues…) consisting of a solid skeleton and pore fluid. Mechanical deformation changes the pore pressure and change in the pore pressure causes mechanical deformation.

A variety of constitutive models can be used for the skeleton, such as: elastic isotropic, orthotropic, thermo-isotropic, thermo-orthotropic, thermo-plastic, Drucker-Prager, Mohr-Coulomb, Cam-clay, creep, plastic-creep, etc.

In this class of multiphysics problems, heat transfer, fluid flow and the mechanical deformation are all coupled. As an example, the fluid flow changes the temperature in the system and this change of temperature causes mechanical deformation changing the boundary conditions for the flow, thus affecting the flow.

Piezoelectric problems are characterized by the coupling of the electric field and mechanical deformation. Applying an electric field to a piezoelectric material causes mechanical deformation and the mechanical deformation causes an electric field.
This phenomenon is the basis for the design of many sensors and actuators.

Piezoelectric Actuation of a Cantilever

An iterative solution of the electric field and structural deformation is
implemented in ADINA TMC module. Users can also implement
nonlinear constitutive relations between the electric displacement
(electric flux) and the strain tensor (piezoelectric matrix).

Examples of Industrial Applications

Microphones

Micropumps

Active vibration control devices

Adaptive structures

Thermal-Electrical Coupling (Joule Heating)

Joule heating is characterized by heat being generated by an electric
current. The heat affects the surrounding media.

In some practical applications, the fluid can be assumed to be inviscid and irrotational. This assumption significantly reduces the computational effort required for calculation of the fluid response and also in the fluid-structure interaction problems.

This class of multiphysics problems is characterized by the coupling between the momentum, continuity and energy equations governing the flow of a mixture of a fluid and other species (solute). The coupling is due to
the dependence of the mixture’s density and viscosity on the solute concentration. Transfer of the solute due to the flow changes the spatial distribution of the mixture density and also its viscosity, consequently affecting the flow pattern, which in turn affects the movement of the solute.